The subject invention relates to an apparatus and method for applying a sheet of jacketing material to a cylindrical product and in particular to an improved semiautomatic apparatus and method for applying a sheet of jacketing material to a cylindrical product, such as but not limited to a tubular pipe insulation product, where the product is retained in a stationary position and the sheet of jacketing material is wrapped about and bonded to the cylindrical outer surface of the product.
Numerous cylindrical products are jacketed to enhance the performance and/or the appearance of such products. While the apparatus and method of the subject invention can be used to apply sheets of Jacketing material to numerous products, the apparatus and method of the subject invention are particularly well suited for applying sheets of jacketing material to pieces of pipe insulation. Jacketed tubular pipe insulation is installed upon the pipes of hot and cold piping systems to retard the flow of heat between the pipes of the system and the ambient environment and conserve energy. Typically, this jacketed tubular pipe insulation has a longitudinally extending slit that passes completely through the tubular wall of the pipe insulation on one side and into the interior of and part of the way through the tubular wall of the pipe insulation on the opposite side of the pipe insulation so that the pipe insulation can be opened, passed over, and closed about a pipe. The pipe insulation is jacketed to enhance the performance of the pipe insulation (e.g. to retard the transmission of water vapor); to prevent the pipe insulation from being exposed to contaminants; to make the pipe insulation more aesthetically pleasing; to protect the pipe insulation from adverse climatic conditions; and to serve as a means for securing and sealing the pipe insulation in place on the pipes of a piping system. Customers, such as installers, expect the pre-applied jackets of the jacketed pipe insulation products to be smooth and conform without creases or wrinkles to the cylindrical outer surfaces of the pieces of pipe insulation; to be correctly registered and aligned with the ends of the pieces of pipe insulation; and to be correctly aligned and registered with the longitudinal slits in the pieces of pipe insulation that enable the pieces of pipe insulation to be opened, passed over, and closed about a pipe.
Currently, sheets of jacketing material are normally applied to pipe insulation by one of two methods. One method is a completely manual method and the other method is an automated method. Both of these methods involve rolling a piece of pipe insulation over a sheet of jacketing material to wrap the sheet of jacketing material about the piece of pipe insulation.
When the manual method for applying a sheet of jacketing material to a piece of pipe insulation is employed, an adhesive is applied to the sheet of jacketing material and the piece of pipe insulation is then placed on and manually rolled over the sheet of jacketing material to wrap the sheet of jacketing material about and bond the sheet of jacketing material to the cylindrical outer surface of the pipe insulation. The manual method of applying a sheet of jacketing material to a piece of pipe insulation can frequently result in the misapplication of the sheet of jacketing material to the piece of pipe insulation. The most common flaw encountered with the manual method of jacketing pipe insulation is the failure of the sheet of jacketing material to be tightly wrapped about the cylindrical outer surface of the piece of pipe insulation. In other words, rather than making a jacketed piece of pipe insulation wherein the jacketing material conforms closely to the cylindrical outer surface of the piece of pipe insulation, a piece of jacketed pipe insulation is produced wherein spaces are left between the jacketing material and the outer surface of the pipe insulation. Since this causes the finished product and thus the installation of the product to look shoddy, installers do not want to use such products. These flaws in the product also cause folds or creases in the jacketing material at the ends of the pieces of pipe insulation and where two pieces of pipe insulation are butted up against each other to be sealed with butt strips, the folds or ceases in the jacketing material are not only aesthetically displeasing, but may also prevent the formation of a vapor tight seal at the butt joint.
Other problems that may be encountered with the manual method of applying a sheet of jacketing material to a piece of pipe insulation include the failure to properly adhere the sheet of jacketing material to and/or to properly register the sheet of jacketing material with the piece of pipe insulation. Typically, the adhesive used is a “hot melt” adhesive that only forms an effective bond when the adhesive is at or above a specific temperature. A wholly manual application of the sheets of jacketing material to the pieces of pipe insulation allows for variations in the time between the application of the “hot melt” adhesive and the application of the sheets of jacketing material to the pieces of pipe insulation that can result in a cooling of the “hot melt” adhesive to temperatures where the adhesive no longer forms an effective bond between the jacketing material and the pipe insulation.
The major problems associated with the current automatic methods for applying sheets of jacketing material to pieces of pipe insulation relate to the high costs involved in the manufacture and installation of such equipment. U.S. Pat. No. 3,755,039, issued Aug. 28, 1973 discloses an example of an automatic apparatus and method of jacketing pipe insulation wherein the pieces of pipe insulation are rolled over the sheets of jacketing material.
Another method and apparatus for applying sheets of jacketing material to the cylindrical outer surfaces of ducts involves rotating the duct and feeding a sheet between a roller and the duct to wrap the sheet around and bond the sheet to the duct. The method and apparatus disclosed in U.S. Pat. No. 3,890,182, issued Jun. 17, 1975 are representative of this type of method and apparatus.